Preparation of the titanium-based composite coagulant PTFS and its coagulation performance on nanoparticles

In this study, a titanium-based coagulant, (i.e., PTFS), with a three-dimensional spatial mesh structure was prepared for the coagulation removal of polystyrene (PS) and titanium dioxide (TiO 2 ) nanoparticles in water. The results of scanning electron microscopy, TGA-DSC, Fourier infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy characterization showed that the PTFS was not a simple mixture of raw materials and a chemical reaction occurred, thereby generating new chemically connected bonds. The optimum removal of PS could reach 92.5% at the dosage of 0.6 mg/L, initial concentration of 70 mg/L, pH of 7, stirring intensity of 350 rpm, settling time of 60 min, and kaolin concentration of 70 mg/L. The best removal rate of TiO 2 could reach 95.3% when the dosage was 0.8 mg/L, the initial concentration was 70 mg/L, the pH was 7, the stirring intensity was 350 rpm, the settling time was 60 min, and the kaolin concentration was 50 mg/L. The flocs produced by PTFS were large and dense. In the early stage of coagulation, the flocculation mechanism was dominated by electroneutralization, and in the middle and late stages of coagulation, adsorption, bridging, and netting were dominated. This study aims to provide a reference for the removal of nanopollutants by coagulation in the actual water treatment process. Practitioner Points A titanium-based coagulant PTFS with a three-dimensional spatial mesh structure was prepared. PTFS effectively removes nano-PS and nano-TiO 2 from water. The flocs produced by PTFS were large and dense flocs. Removal of PS and TiO 2 by PFTS has been a combination of multiple coagulation mechanisms. Graphical The titanium-based coagulant PTFS was prepared to remove PS and TiO 2 nanoparticles from water. The removal of PS and TiO 2 by coagulation was a combination of compression bilayer, adsorption and electroneutralization, net trapping and sweeping, and adsorption and bridging mechanisms.